SOLID SOLUBILITIES OF Ce, Nd AND Y IN α—Fe AT ROOM TEMPERATURE

Using the thermodynamic formula of solid solubility in dilute solution, the solid solubilities of Ce. Nd and Y in α-Fe at room temperature have been calculated The results are 48, 32 and 1(×10~(-4)wt. -％) respectively and the mechanism influencing the values of solid solubilities are also discussed.     

ELEVATED AND ROOM TEMPERATURE MECHANICAL BEHAVIOR OF BORON DOPED NiAl ALLOYS

The effects of boron addition on defect hardening at room temperature and on high temperatrue creep properties are investigated in the B_2 NiAl intermetallic comopound.It is foundthat boron addition is effective on inereasing the room temperature hardeness on theNi-rich side but it has no effect on the Al rich side of stoichiometry.These obseryationsare attributed to interstitial dissolution of boron in Ni-rich NiAl and to a lack of solubilityand also due to an enrichment at grain boundaries on the Al-rich side.The similar effect is found in high temperature creep resistance of NiAl by bofom addition.The high temperature creep resistance increases on the Ni-rich side but it does not affect the Al-rich side ofoff-stoiciometry.     

TOUGHENING OF IN SITU SYNTHESIZED MoSi_2-SiC COMPOSITE AT ROOM TEMPERATURE

二．InttodttCt1OllMoslZ meets thebaslc requirements for ahlgh temperature structuralmaterlal．凡reXampk,nhas a hi吵一king pdntd2030”C,rd扒IV*y high re幻s枯nCe扣high比m－perature。ldatlon,alow density of6．249/cm’,ahlgh modulus,adequate strength at1200－     

THE RATE OF TEMPERATURE INCREASE AND THE KINETICS OF PbS AND PbO IRRADIATED WITH MICROWAVE

The rate of temperature increase and the kinetics of PbS and PbO, irradiated with microwaves, have been studied. According to the experimental data, the interaction between PbS and PbO is nonisothermal, and the activation energy becomes lower and the rate of interaction becomes faster with microwave irradiation than with conventional heating.     

ABSORPTION KINETICS OF HYDROGEN SULPHIDE USING ISOTHERMAL AND ISOVOLUMETRIC METHOD

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REDUCTIVE LEACHING OF MANGANESE NODULE BY CHALCOPYRITE INDILUTE HCL SOLUTION

ＲＥＤＵＣＴＩＶＥＬＥＡＣＨＩＮＧＯＦＭＡＮＧＡＮＥＳＥＮＯＤＵＬＥＢＹＣＨＡＬＣＯＰＹＲＩＴＥＩＮＤＩＬＵＴＥＨＣＬＳＯＬＵＴＩＯＮＧｕｏ；Ｘｕｅｙｉ（ＤｅｐａｒｔｍｅｎｔｏｆＮｏｎｆｅｒｒｏｕｓＭｅｔａｌｌｕｒｇｙ，ＣｅｎｔｒａｌＳｏｕｔｈＵｎｉ...     

ROOM TEMPERATURE AND 750℃ ISOTHERMAL SECTION OF Ag-Pd-Gd(Gd≤25 AT.-%)PHASE DIAGRAM

The room temperature section and the 750℃ isothermal section of the Ag-Pd-Gd ternaryphase diagram containing 0—25 at.-% Gd are constructed by X—ray diffraction analysis andoptical microscopy.Each section consists of 3 single phase regions,3 bi-phase regions and Itri-phase region respectively.     

THE STRUCTURE CHANGE OF γ-TiAl IRRADIATED BY 50keV XENON IONS AT ROOM TEMPERATURE

1. Introduction In the fusion reactor development, the TiAl compounds are one of the candidate struc- tural materials, because both Ti and Al are the elements with small neutron-induced radioactivity. Grala et al.(1l measured the micro-hardness caused by neutron irradiation with a dose of about lO2Sons/m2 at 498K and found a distinct hardness increase compared with unirradiated material. Several papers reported that the radiation induced vacancy and defect clusters in -y-TiAI crystals inv…     

RECOVERING RE FROM LEACHING LIQUOR OF RARE EARTH ORE BY EXTRACTION

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KINETICS OF LEACHING SPHALERITE WITH PYROLUSITE SIMULTANEOUSLY BY MICROWAVE IRRADIATION

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软锰矿两矿法选择性浸出

采用黄铁矿软锰矿酸浸工艺直接浸出软锰矿，浸出过程中Ｆｅ、Ｓｉ、Ａｌ等杂质残留在矿石内，形成残留物层。通过控制浸出的动力学条件，可以实现锰的选择性浸出，降低浸出液中的杂质含量。扫描电镜和电子能谱试验表明，锰的浸出过程应以未反应收缩核模型描述     

KINETICS OF GOLD LEACHING FROM SULFIDE GOLD CONCENTRATES WITH THIOSULFATE SOLUTION

The reaction process for leaching gold from sulfide gold concentrates containing copperwith ammonia-ammonium thiosulfate solution containing copper(Ⅱ)can be divided into initialstage and later stage of reaction.Initial stage of reaction is controlled by interface reaction.Lat-er stage of reaction is controlled by diffusion process of reaction through solid products layer.Whole leaching process is under the control of corrosion reaction of pyrite bearing gold.Actionof ammonium sulfate in the system is probably as follows:(1)NH_4~ and NH_3 forms a buffer so-lution;(2)SO_4~(2-)ion inhibites the oxidation and decomposition of S_2O_3~(2-)ion.Cu~(2 )ion in thesystem acts as an oxidant and oxygen makes the Cu~(2-)regenerate.     

含碳球团还原过程动力学及模型

本文研究了不同条件下含碳球团在Ｎ_２气氛中的还原过程．结果发现，球团中心的还原速度大于其边缘速度，固相反应Ｆｅ_ｘＯ_ｙ＋ｙＣ＝ｘＦｅ＋ｙＣＯ不是含碳球团还原过程的主要反应；以往的含碳球团还原过程模型不能正确地描述其反应过程．本文提出了含碳球团还原过程的新观点，并以此观点为基础建立了含碳球团还原过程模型，试验证明该模型能很好地描述含碳球团的还原过程．     

含Ti高炉渣酸解动力学

研究了363-383 K范围内,使用稀硫酸(20％-60％)酸解含Ti高炉渣的酸解动力学.实验条件下的化学反应过程为化学反应控制,用生成固体产物层的未反应核缩减模型可描述为1-(1-x)1/3=kMBcnAt/(roρwB)=Kt.将实验结果与模型关联,求出的酸解反应级数n=1.222,表观活化能为87.01 kJ/mol,K=5.090×104×(10.59+1/r0)cA1.222e-10.465×103/T.通过实验验证,TiO2酸解率低于90％时与模型很好符合.     

FeCl3浸取含Au复杂硫化矿的动力学研究

研究了FeCl_3溶液浸取复杂含金硫化精矿中有价金属Cu,Ag,Pb和Zh的过程,考察了主要过程参量对浸取速率的影响.实验数据用非线性回归方法处理,给出动力学模型,说明精矿中Cu的溶解过程由表面化学反应控制,其速率是Fe~(3+)的0.5级和Cl~(-)的零级反应.实验条件下Cu,Ag,Ph和Zn的最终浸取率分别达到96,95,90和91%,超过90%的Fe进入浸取液,总硫的70%以上转化为元素硫,而Au的浸取率则小于3%表明FeCl_3溶液浸取是含Au复杂硫化精矿预处理并回收有价金属的有潜力的方法     

ACTIVATION MECHANISM OF AlCl_3 DURING THE LEACHING OF Cu-Ni ORE WITH FeCl_3

After Cu-Ni ore powder pre-soaked in AlCl_3 solution.the leaching ratios of copper andnickel can increase obviously.By X-ray diffraction analyses,electron energy spectrum analysesand electrochemical experiments,it is affirmed that,the activation of aluminum ion includestwo aspects:one is the surface change of the ore by the absorption of hydrolysates,and the oth-er is the change of semiconductor characteristics of the metal sulfides by impurity aluminum ionentering the lattice,so that leaching reactions are accelerated.     

IMPROVEMENT OF DUCTILITY AND TOUGHNESS OF Ni-RICH NiAl AT ROOM TEMPERATURE

In rapidly solidified Ni-34.6 at-% Al alloy,when the cooling the rate during solidificationreached the order of 10~6 K/s,the size of the microstructures,such as the grains andsubstructure of the martensite,decreased dramatically.The various kinds of interfaces withhigh density and homogeneous distribution resisted effectively the propagation of the cracksand resulted in localized plastic deformation ahead of the tips of microcracks.The ductilityand toughness at room temperature of the Ni-rich NiAl may be improved considerably.